Parallel distributed processing and neuropsychology: A neural network model of Wisconsin card sorting and verbal fluency

Neural networks can be used as a tool in the explanation of neuropsychological data. Using the Hebbian Learning Rule and other such principles as competition and modifiable interlevel feedback, researchers have successfully modeled a widely used neuropsychological test, the Wisconsin Card Sorting Test. One of these models is reviewed here and extended to a qualitative analysis of how verbal fluency might be modeled, which demonstrates the importance of accounting for the attentional components of both tests. Difficulties remain in programming sequential cognitive processes within a parallel distributed processing (PDP) framework and integrating exceedingly complex neuropsychological tests such as Proverbs. PDP neural network methodology offers neuropsychologists co-validation procedures within narrowly defined areas of reliability and validity.     

Multimodal encoding in a simplified model of intracellular calcium signaling

Many cells use calcium signaling to carry information from the extracellular side of the plasma membrane to targets in their interior. Since virtually all cells employ a network of biochemical reactions for Ca²⁺ signaling, much effort has been devoted to understand the functional role of Ca²⁺ responses and to decipher how their complex dynamics is regulated by the biochemical network of Ca²⁺-related signal transduction pathways. Experimental observations show that Ca²⁺ signals in response to external stimuli encode information via frequency modulation (FM) or alternatively via amplitude modulation (AM). Although minimal models can capture separately both types of dynamics, they fail to exhibit different and more advanced encoding modes. By arguments of bifurcation theory, we propose instead that under some biophysical conditions more complex modes of information encoding can also be manifested by minimal models. We consider the minimal model of Li and Rinzel and show that information encoding can occur by AM of Ca²⁺ oscillations, by FM or by both modes (AFM). Our work is motivated by calcium signaling in astrocytes, the predominant type of cortical glial cells that is nowadays recognized to play a crucial role in the regulation of neuronal activity and information processing of the brain. We explain that our results can be crucial for a better understanding of synaptic information transfer. Furthermore, our results might also be important for better insight on other examples of physiological processes regulated by Ca²⁺ signaling.     

Evaluating expectations about negative emotional states of aggressive boys using Bayesian model selection

Researchers often have expectations about the research outcomes in regard to inequality constraints between, e.g., group means. Consider the example of researchers who investigated the effects of inducing a negative emotional state in aggressive boys. It was expected that highly aggressive boys would, on average, score higher on aggressive responses toward other peers than moderately aggressive boys, who would in turn score higher than nonaggressive boys. In most cases, null hypothesis testing is used to evaluate such hypotheses. We show, however, that hypotheses formulated using inequality constraints between the group means are generally not evaluated properly. The wrong hypotheses are tested, i.e.. the null hypothesis that group means are equal. In this article, we propose an innovative solution to these above-mentioned issues using Bayesian model selection, which we illustrate using a case study.     

Beyond procedure's content: the role of accessibility experiences and personal uncertainty in procedural justice judgements

Procedural justice concerns play a critical role in economic settings, politics, and other domains of human life. Despite the vast evidence corroborating their relevance, considerably less is known about how procedural justice judgments are formed. Whereas earlier theorizing focused on the systematic integration of content information, the present contribution provides a new perspective on the formation of justice judgments by examining the influence of accessibility experiences. Specifically, we hypothesize that procedural justice judgments may be formed based on the ease or difficulty with which justice-relevant information comes to mind. Three experiments corroborate this prediction in that procedures were evaluated less positively when the retrieval of associated unfair aspects was easy compared to difficult. Presumably this is because when it feels easy (difficult) to retrieve unfair aspects, these are perceived as frequent (infrequent), and hence the procedure as unjust (just). In addition to demonstrating that ease-of-retrieval may influence justice judgments, the studies further revealed that reliance on accessibility experiences is high in conditions of personal certainty. We suggest that this is because personal uncertainty fosters systematic processing of content information, whereas personal certainty may invite less taxing judgmental strategies such as reliance on ease-of-retrieval.     

Natality and mortality: rethinking death with Cavarero

In this article I rethink death and mortality on the basis of birth and natality, drawing on the work of the Italian feminist philosopher Adriana Cavarero. She understands birth to be the corporeal event whereby a unique person emerges from the mother’s body into the common world. On this basis Cavarero reconceives death as consisting in bodily dissolution and re-integration into cosmic life. This impersonal conception of death coheres badly with her view that birth is never exclusively material but always has ontological significance as the appearance of someone new and singular in the world of relations with others. This view of birth calls for a relational conception of death, which I develop in this article. On this conception, death is always collective, affecting all those with whom the one who dies has maintained relations: As such, our different deaths shade into one another. Moreover, because each person is unique in virtue of consisting of a unique web of relations with others, death always happens to persons as webs of relations. Death is relational in this way as a corporeal, and specifically biological, phenomenon, to which we are subject as bodily beings and as interdependent living organisms. I explore this with reference to Simone de Beauvoir’s memoir of her mother’s death from cancer. Finally I argue that, on this relational conception, death is something to be feared.     

Investigating Physiological and Self-Reported Mediators of Stereotype Lift Effects on a Motor Task

Achievement gaps between social groups may result from stereotype threat effects but also from stereotype lift effects—the performance boost caused by the awareness that an outgroup is negatively stereotyped. We examined stereotype lift and threat effects in the motor domain and investigated their mediation by task involvement and self-confidence, measured by heart rate reactivity and self-reported indices. Males and females performed a balance task about which negative stereotypes about either males or females were given. No gender information was given in a control condition. Results showed no stereotype threat but a stereotype lift effect, participants performing significantly better after negative outgroup stereotypes were explicitly linked to performance on the balance task compared to the control condition. Concerning males, this effect was mediated by higher self-confidence and task involvement. The implications of these results for understanding the gender inequalities in the motor domain are discussed.     

The Effect of Negative Incentives in Serial Learning: VII. Theory of Punishment

Eighty three-, four-, five-, and six-year-old boys and girls were presented with experimental conditions where context, transformational complexity, and verbal cue were varied, Two experimental tasks, a perceptually Concrete and an Abstract task, were included and Ss were assigned to a Verbal Cue or a Nonverbal Cue condition. All Ss responded to both the present progressive and the past tenses. Results revealed significant effects of the Age and Tense factors, and improved performance on Comprehension over Production. Younger children made fewer overall errors than older ones. Ss performed better on the present progressive than on the past tense on the perceptually Concrete task, while the reverse was true on the Abstract task. These findings demonstrate that language performance is the result of a complex interrelationship between transformational complexity and the perceptual properties of linguistic structures.